The objectives of the proposed research are to provide an experimental analysis of the effects of drugs of abuse upon sensory functions and motor performance in non-human primates. Animal psychophysical procedures will be used to test the effects on a range of pharmacologic agents, including barbiturates, benzodiazepines, and phencyclidine-like compounds upon absolute auditory and visual thresholds and upon reaction times to auditory and visual stimuli in non-restrained laboratory baboons. The results will provide normative data on the within-class and between-class effects of drugs of abuse on sensory function and motor performance across a range of doses, and will provide information relevant to drug scheduling and clinical evaluation of functional decrements produced by such compounds.